1. Field of the Invention
The present invention relates to a marking determining method and a related device.
2. Description of Related Art
Such a marking determining device is already known in the art, e.g. from the Internet Engineering Task Force (IETF) document “A Two rate three colour marker” with reference RFC 2698 from the authors J. Heinanen and R. Guerin, published in September 1999. Therein, a marking determining device is described, metering traffic reservation parameters of an incoming IP packet stream and subsequently marking its packets, based on two traffic reservation parameters, called the token count of the respective green and yellow token buckets, either with one of a pre-assigned packet loss probability, called marking the packets either with a red, yellow or green colour. This metering is performed in one of two modes, either in a first mode which assumes that the packets of the IP stream do not have a pre-assigned loss probability, called the colour-blind mode or in a second mode assuming that each of the packets does have a pre-assigned packet loss probability called the colour aware mode.
In case of this first mode of marking, the actual value of the traffic reservation parameters determines which packet loss priority the packet is assigned or marked.
In the colour aware mode the pre-assigned priority, i.e. that is the colour of the packet is taken into account and the predetermined rules and condition are such that the network resources dedicated to high priority packets, called green tokens, never are available for a medium priority packet called a yellow packet and the network resources dedicated to high and medium priority packets are not available for the low priority packets, called red packets. In this way the network resources are reserved for high priority packets in first instance and for medium priority packets in a second instance. In case there are no incoming high priority packets in the IP-packet stream, the network resources dedicated to these high priority packets is not used and gets consequently lost meaning that the reserved resources are not used.